https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94510
Bug ID: 94510
Summary: nullptr_t implicitly cast to zero twice in std::array
Product: gcc
Version: 9.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: kndevl at outlook dot com
Target Milestone: ---
`std::array<int, 3> arr{ nullptr, 0, 0 };` is expected to fail to compile
similar to how `std::array<int, 3> arr{ nullptr, 0, 1 };` fails. What I infer
is that if all elements are effectively zero, type conversions are not checked.
This makes sense if a variable of static storage duration is initialized to
zero and std::array constructor can ignore the arguments in the initializer if
all arguments are implicitly zero.
Is there anything on the C++ standard that allows this optimization I am
missing here?
# This works fine, as expected
`g++ -save-temps -c not-bug.cpp`
> not-bug.cpp: In function ‘void test()’:
> not-bug.cpp:4:43: error: cannot convert ‘std::nullptr_t’ to ‘int’ in
> initialization
> 4 | std::array<int, 3> arr{ nullptr, 0, 1 };
# This compiles fine, but this should error out
`g++ -save-temps -c bug.cpp`
I built the tip of gcc yesterday. It had the same bug.
Any pointers on how I can go about debugging this?
- Does type checking happen during GENERIC stage?
- How do I print the source string corresponding to a TREE struct?
